ABUJA (Reuters) - A gun battle in a Nigerian border town that looked likely to have killed dozens last week involved forces from neighboring Chad and Niger, who were surprised by the firepower they faced there, officials said on Tuesday.

The joint force was assembled after intelligence that Islamist militants Boko Haram had moved into Baga, a fishing town in northeast Nigeria on the shores of Lake Chad, on the Chadian border and close to Niger, Nigeria's military said.

Nigerien and Chadian officials confirmed their involvement.

There was still no confirmation of the death toll from Friday's fighting, but a Nigerian military source said dozens may have died. The Nigerian Red Cross said they were trying to check reports from locals that 187 people had been killed, but had not yet gained security clearance to go into Baga.

(Reporting by Tim Cocks in Abuja; Additional reporting by Abdoulaye Massalaki in Niamey and Madjiasra Nako in Ndjamena; Editing by Louise Ireland)